1. Field of the Invention
This invention relates to a connector used for connection of electric wires.
2. Description of the Related Art
A motor vehicle which is a moving body includes a great variety of electronic devices. The motor vehicle have wire harnesses arranged to transfer an electric power and control signal to the electronic devices. The wire harness includes a plurality of electric wires and a plurality of connectors. The electric wire is a coated wire consisting of a conductive core and an insulating coating which coats the core.
The connector includes a conductive terminal metal fitting and an insulating connector housing. The terminal metal fitting is attached to the end of the electric wire so that it is electrically connected to the core. The connector housing houses the terminal fitting. The connector housed in the connector housing is connected to the connector of the electric device to transfer a control signal to the electronic device.
The terminal metal fitting has been proposed which is provided with a pair of contact pieces sandwiching a conductor such as a flat circuit body inclusive of an FPC (Flexible Printed Circuit), FFC (Flexible Flat Cable), etc.(see JP-A-9-63718). In such terminal fittings, with a complementary conductor (terminal fitting) being located on the surface of the one contact piece, the other contact piece is adapted to urge the conductor in the complementary connector toward the one contact piece.
In the connector, i.e. terminal fittings conventionally employed, the urging force of the other contact piece was kept above a predetermined value. Further, in the terminal metal fittings, the rigidity of the pair of contact pieces were increased so that they are difficult to be elastically deformed, thereby sandwiching the complementary conductor between the pair of contact pieces. The terminal metal fitting intends to prevent the complementary conductor sandwiched between the contact pieces from being shifted, thereby preventing fretting corrosion from occurring at these contact points. In this way, the conventional terminal metal fitting was electrically connected to the complementary conductor.
Meanwhile, the conventional terminal metal fittings were electrically connected to the complementary conductor in such a way that the rigidity of the contact pieces is increased and the urging force thereof is kept above a predetermined value.
On the other hand, the motor vehicle with the wire harness arranged therein includes a great variety of electronic devices. Therefore, there is a tendency that the number of electric wires is increased so that the wire harness has an increased weight and is upsized.
In order to suppress the increase in weight and upsizing, the connector accommodated a larger number of terminal metal fittings (realization of multi-poles of the terminal metal fitting) and downsized the terminal fitting. In order to facilitate the arrangement of the wire harness, it has been demanded that the force applied when the connector is coupled with a complementary connector is decreased (realization of low insertion force).
When the terminal metal fitting is down-sized, it becomes to difficult to assure the urging force over a predetermined value and also difficult to surely connect the terminal metal fittings at issue to the complementary conductor. This may generate the fretting corrosion at the contacts described above. The realization of the multi-poles of the terminal metal fitting and low insertion force of the connector requires the urging force for a single terminal metal fitting to be suppressed. This further makes it more difficult to assure the urging force over the predetermined value, and hence to connect the terminal metal fittings to the complementary conductor. This leads to an increase in the possibility of fretting corrosion at the contact points described above.